there must be a reason why they got rid of them...
(but RBR will know best i think)

I still see quite a few high speed offroad vehicles that use J-arms. A lot of the aftermarket long travel suspension kits use that stuff, since its easier to package the rest of the suspension with that. Not sure its a good fit for system that travels as little as the F1 cars do. Not sure its bad either.

But their 2011 car is apparently faster than anyone else's 2012 so far in testing. So, a slightly slower season this year?

Two things against that:
1) As Merc were only there to evaluate the new tires, they could push their car to the maximum to get real-life tire data. The other teams, with brand-new cars, did not go for maximum performance yet, but played it safe, focusing on consistency and creating pre-defined scenarios in order to gather base data about the car.

2) We had some massive rule changes regarding diffusers and so on, which is why the 2012 cars are not slight evolutions of the 2011 models but more or less completely new. So the whole process of "optimizing the package" has to restart. The 2011 Merc thus is developed to the maximum, while the all-season development race has not yet begun for the new cars.

Given how close the new 2012 cars, even with both restrictions explained above, come to the Merc, I guess they will be as fast if not faster than the 2011 cars.

____________________________Battered and weary after the craziness of the 1960s, the self-righteousness of the 1970s and the greed of the 1980s, I want to go home again, oh, so desperately - home to that land of drive-in restaurants and Chevy Bel-Airs, making out and rock 'n' roll and drag races and Studebakers, Elvis and James Dean and black leather jackets. Not that I ever owned a black leather jacket.
(Roger Ebert)

Not quite true, many teams already have the first 4+ races of development locked out.

I stand corrected. But that's still a difference in development compared to Merc's 2011 car.

____________________________Battered and weary after the craziness of the 1960s, the self-righteousness of the 1970s and the greed of the 1980s, I want to go home again, oh, so desperately - home to that land of drive-in restaurants and Chevy Bel-Airs, making out and rock 'n' roll and drag races and Studebakers, Elvis and James Dean and black leather jackets. Not that I ever owned a black leather jacket.
(Roger Ebert)

None of the F1 commentards seem to have picked up on this, but the Red Bull has no lower wishbone. They've simply thrown away the two large structural members directly in front of the diffuser.

This was brought to my attention when I was talking F1 w/ my coworker, while we were talking about the RB8 he mentioned the lower rear wishbone and how it acted as a shroud for the axleshafts.

Here's the article he read it from:

With such a high top wishbone the lower rear wishbone is able to mount higher too. This wishbone is now effectively at the same height as the driveshaft. Not only is it inline, but the wishbone forms an shroud ahead of the driveshaft to offset the negative aerodynamic effect of the rotating shaft, in the critical area above the diffuser (Note: Fully shrouded driveshafts are banned). While this all appears to be logical, the lower wishbone is not a splayed as the upper wishbone. Having the inboard mountings very close to each other is not so good from a loading perspective, so there must be a reason to make the wishbone in such a compromised shape. Again this might suggest the new exhaust needs the wishbone in a certain position to work effectively.